Tactile stimulation disambiguates the perception of visual motion paths

Although visual perception traditionally has been considered to be impenetrable by non-visual information, there are a rising number of reports discussing cross-modal influences on visual perception. In two experiments, we investigated how coinciding vibrotactile stimulation affects the perception of two discs that move toward each other, superimpose in the center of the screen, and then move apart. Whereas two discs streaming past each other was the dominant impression when the visual event was presented in isolation, a brief coinciding vibrotactile stimulation at the moment of overlap biased the visual impression toward two discs bouncing off each other (Experiment 1). Further, the vibrotactile stimulation actually changed perceptual processing by reducing the amount of perceived overlap between the discs (Experiment 2), which has been demonstrated to be associated with a higher proportion of bouncing impressions. We propose that tactile-induced quantitative changes in the visual percept might alter the quality of the visual percept (from streaming to bouncing), thereby adding to the understanding of how cross-modal information interacts with early visual perception and how this interaction influences subsequent visual impressions.